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Oracle Fusion Middleware Java API Reference for Oracle ADF Mobile Client 11g Release 1 (11.1.1) E17503-02 |
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public interface Expression
Base class for the expression subclasses ValueExpression
and MethodExpression
,
implementing characterstics common to both.
All expressions must implement the equals()
and hashCode()
methods
so that two expressions can be compared for equality. They are redefined abstract in this class
to force their implementation in subclasses.
All expressions must also be Serializable
so that they can be saved and restored.
Expression
s are also designed to be immutable so that only one instance needs to
be created for any given expression String / FunctionMapper
. This allows a container to
pre-create expressions and not have to re-parse them each time they are evaluated.
Method Summary | |
---|---|
boolean |
equals(java.lang.Object obj)
Determines whether the specified object is equal to this Expression . |
java.lang.String |
getExpressionString()
Returns the original String used to create this Expression , unmodified. |
int |
hashCode()
Returns the hash code for this Expression . |
boolean |
isLiteralText()
Returns whether this expression was created from only literal text. |
Method Detail |
---|
java.lang.String getExpressionString()
Expression
, unmodified.
This is used for debugging purposes but also for the purposes of comparison (e.g. to ensure the expression in a configuration file has not changed).
This method does not provide sufficient information to re-create an expression. Two different
expressions can have exactly the same expression string but different function mappings.
Serialization should be used to save and restore the state of an Expression
.
boolean equals(java.lang.Object obj)
Expression
.
The result is true
if and only if the argument is not null
, is
an Expression
object that is the of the same type (ValueExpression
or MethodExpression
), and has an identical parsed representation.
Note that two expressions can be equal if their expression Strings are different. For
example, ${fn1:foo()}
and ${fn2:foo()}
are equal if their
corresponding FunctionMapper
s mapped fn1:foo
and
fn2:foo
to the same method.
equals
in class java.lang.Object
obj
- the Object
to test for equality.
true
if obj
equals this Expression
;
false
otherwise.Hashtable
,
Object.equals(java.lang.Object)
int hashCode()
Expression
.
See the note in the equals(java.lang.Object)
method on how two expressions can be equal if their
expression Strings are different. Recall that if two objects are equal according to the
equals(Object)
method, then calling the hashCode
method on each
of the two objects must produce the same integer result. Implementations must take special
note and implement hashCode
correctly.
hashCode
in class java.lang.Object
Expression
.equals(java.lang.Object)
,
Hashtable
,
Object.hashCode()
boolean isLiteralText()
This method must return true
if and only if the expression string this
expression was created from contained no unescaped EL delimeters (${...}
or
#{...}
).
true
if this expression was created from only literal text;
false
otherwise.
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Oracle Fusion Middleware Java API Reference for Oracle ADF Mobile Client 11g Release 1 (11.1.1) E17503-02 |
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